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. 2016 Jun 21;6:66. doi: 10.3389/fcimb.2016.00066

Figure 3.

Figure 3

Yersinia susceptibility to killing by macrophages. Y. pseudotuberculosis strains were used to infect murine macrophage-like J774-1 cells. Bacterial cells with a compromised T3SS were more rapidly phagocytosed and killed by these immune cells. Bacterial survival as measured by CFU/ml was determined at 2 h (A) and 6 h (B) post-infection. The results are expressed as a mean of at least six independent assays ± the standard deviation (Unpaired t-test with Welch's correction; n = 12–22 cells; α = 0.05; ns, not significant, P > 0.05; **P ≤ 0.01; ***P ≤ 0.001). Of all the site-directed point mutants examined, bacteria producing YopN288(scramble)293, TyeAY3A and TyeAL5A still show comparable viability to parental bacteria after 6 h, whereas Mutant 5 (YopN279STOP) is particularly compromised to the extent of null mutants in yopN or tyeA.. Strains: Parent (YopNnative), YPIII/pIB102; ΔyopB, yopD double mutant, YPIII/pIB619; ΔyopN null mutant, YPIII/pIB82; ΔtyeA null mutant, YPIII/pIB801a; ΔyopN, tyeA double mutant, YPIII/pIB8201a; Mutant 1–YopN288(scramble)293, YPIII/pIB8213; Mutant 2–YopN288STOP, YPIII/pIB8212; Mutant 3–YopN279(F+1), 287(F−1), YPIII/pIB8208; Mutant 4–YopN279(F+1), 287STOP, YPIII/pIB8207; Mutant 5–YopN279STOP, YPIII/pIB8209; YopNW279G, YPIII/pIB8223; TyeAY3A, YPIII/pIB8221; TyeAL5A, YPIII/pIB8222; TyeAF8A, YPIII/pIB8220; TyeAF33A, YPIII/pIB8219.